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                <p>欢迎来到<a href="https://anzhiruoxi123.github.io/">鸿鹄会</a>让我们一起学习吧！<br>我的邮箱<a href="https://anzhiruoxi123.github.io/">2779372950@qq.com</a></p>
<h4 id="一、在studentsdb数据库中使用SELECT语句进行基本查询。"><a href="#一、在studentsdb数据库中使用SELECT语句进行基本查询。" class="headerlink" title="一、在studentsdb数据库中使用SELECT语句进行基本查询。"></a>一、在studentsdb数据库中使用SELECT语句进行基本查询。</h4><h6 id="1-在student-info表中，查询每个学生的学号、姓名、出生日期信息。"><a href="#1-在student-info表中，查询每个学生的学号、姓名、出生日期信息。" class="headerlink" title="(1)在student_info表中，查询每个学生的学号、姓名、出生日期信息。"></a>(1)在student_info表中，查询每个学生的学号、姓名、出生日期信息。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名`,c.`出生日期` FROM student_info c;</span><br></pre></td></tr></table></figure>
<h6 id="2-查询student-info表学号为-0002的学生的姓名和家庭住址。"><a href="#2-查询student-info表学号为-0002的学生的姓名和家庭住址。" class="headerlink" title="(2)查询student_info表学号为 0002的学生的姓名和家庭住址。"></a>(2)查询student_info表学号为 0002的学生的姓名和家庭住址。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`姓名`,c.`家族住址` FROM student_info c</span><br><span class="line"> <span class="built_in">where</span> c.`学号`=<span class="string">&#x27;0002&#x27;</span>;</span><br></pre></td></tr></table></figure>
<h6 id="3-查询student-info表所有出生日期在95年以后的女同学的姓名和出生日期。"><a href="#3-查询student-info表所有出生日期在95年以后的女同学的姓名和出生日期。" class="headerlink" title="(3)查询student_info表所有出生日期在95年以后的女同学的姓名和出生日期。"></a>(3)查询student_info表所有出生日期在95年以后的女同学的姓名和出生日期。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`姓名`,c.`出生日期` FROM student_info c</span><br><span class="line"> WHERE c.`出生日期` &gt; <span class="string">&#x27;1995-01-01&#x27;</span>AND c.`性别`=<span class="string">&#x27;女&#x27;</span>;</span><br></pre></td></tr></table></figure>
<h4 id="二、使用select语句进行条件查询。"><a href="#二、使用select语句进行条件查询。" class="headerlink" title="二、使用select语句进行条件查询。"></a>二、使用select语句进行条件查询。</h4><h6 id="1-在grade表中查询分数在70-80范围内的学生的学号、课程编号和成绩。"><a href="#1-在grade表中查询分数在70-80范围内的学生的学号、课程编号和成绩。" class="headerlink" title="(1)在grade表中查询分数在70-80范围内的学生的学号、课程编号和成绩。"></a>(1)在grade表中查询分数在70-80范围内的学生的学号、课程编号和成绩。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">SELECT * FROM grade d</span><br><span class="line">SELECT d.`学号`,d.`课程编号`,d.`分数` FROM grade d </span><br><span class="line"> WHERE d.`分数` BETWEEN 70 AND 80;</span><br></pre></td></tr></table></figure>
<h6 id="2-在grade表中查询课程编号为0002的学生的平均成绩。"><a href="#2-在grade表中查询课程编号为0002的学生的平均成绩。" class="headerlink" title="(2)在grade表中查询课程编号为0002的学生的平均成绩。"></a>(2)在grade表中查询课程编号为0002的学生的平均成绩。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT AVG(d.`分数`) AS 分数 FROM grade d</span><br><span class="line"> WHERE d.`课程编号`=0002;</span><br></pre></td></tr></table></figure>
<h6 id="3-在grade表中查询选修课程编号为0003的人数和该课程有成绩的人数。"><a href="#3-在grade表中查询选修课程编号为0003的人数和该课程有成绩的人数。" class="headerlink" title="(3)在grade表中查询选修课程编号为0003的人数和该课程有成绩的人数。"></a>(3)在grade表中查询选修课程编号为0003的人数和该课程有成绩的人数。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT COUNT(d.`分数`) FROM grade d</span><br><span class="line"> WHERE d.`课程编号`=0003;</span><br></pre></td></tr></table></figure>
<h6 id="4-查询student-info的姓名和出生日期，查询结果按出生日期从大到小排序。"><a href="#4-查询student-info的姓名和出生日期，查询结果按出生日期从大到小排序。" class="headerlink" title="(4)查询student_info的姓名和出生日期，查询结果按出生日期从大到小排序。"></a>(4)查询student_info的姓名和出生日期，查询结果按出生日期从大到小排序。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`姓名`,c.`出生日期` FROM student_info c </span><br><span class="line"> ORDER BY c.`出生日期` DESC;</span><br></pre></td></tr></table></figure>
<h6 id="5-查询所有姓名“张”的学生的学号和姓名。"><a href="#5-查询所有姓名“张”的学生的学号和姓名。" class="headerlink" title="(5)查询所有姓名“张”的学生的学号和姓名。"></a>(5)查询所有姓名“张”的学生的学号和姓名。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名` FROM student_info c</span><br><span class="line"> WHERE c.`姓名` LIKE <span class="string">&#x27;张%&#x27;</span>;</span><br></pre></td></tr></table></figure>
<h4 id="三、对student-info表，查询学生的学号、姓名、性别、出生日期及家庭住址，查询结果先按照性别的由小到大排序，性别相同的再按学号由大到小排序。"><a href="#三、对student-info表，查询学生的学号、姓名、性别、出生日期及家庭住址，查询结果先按照性别的由小到大排序，性别相同的再按学号由大到小排序。" class="headerlink" title="三、对student_info表，查询学生的学号、姓名、性别、出生日期及家庭住址，查询结果先按照性别的由小到大排序，性别相同的再按学号由大到小排序。"></a>三、对student_info表，查询学生的学号、姓名、性别、出生日期及家庭住址，查询结果先按照性别的由小到大排序，性别相同的再按学号由大到小排序。</h4><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名`,c.`性别`,c.`出生日期`,c.`家族住址` FROM student_info c</span><br><span class="line">  ORDER BY c.`性别`,c.`学号`DESC;</span><br></pre></td></tr></table></figure>
<h4 id="四、使用GROUP-BY子句查询grade表中各个学生的平均成绩。"><a href="#四、使用GROUP-BY子句查询grade表中各个学生的平均成绩。" class="headerlink" title="四、使用GROUP BY子句查询grade表中各个学生的平均成绩。"></a>四、使用GROUP BY子句查询grade表中各个学生的平均成绩。</h4><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">SELECT AVG(d.`分数`) AS 平均成绩 FROM grade d;</span><br></pre></td></tr></table></figure>
<h4 id="五使用UNION运算符针student-info表中姓“刘”的学生的学号、姓名与姓“张”的学生的学号、姓名返回在一个表中。"><a href="#五使用UNION运算符针student-info表中姓“刘”的学生的学号、姓名与姓“张”的学生的学号、姓名返回在一个表中。" class="headerlink" title="五使用UNION运算符针student_info表中姓“刘”的学生的学号、姓名与姓“张”的学生的学号、姓名返回在一个表中。"></a>五使用UNION运算符针student_info表中姓“刘”的学生的学号、姓名与姓“张”的学生的学号、姓名返回在一个表中。</h4><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名` FROM  student_info c WHERE c.`姓名` LIKE <span class="string">&#x27;刘%&#x27;</span></span><br><span class="line">UNION</span><br><span class="line">SELECT c.`学号`,c.`姓名` FROM  student_info c WHERE c.`姓名` LIKE <span class="string">&#x27;张%&#x27;</span>;</span><br></pre></td></tr></table></figure>
<h4 id="六嵌套查询"><a href="#六嵌套查询" class="headerlink" title="六嵌套查询"></a>六嵌套查询</h4><h6 id="1-在student-info表中查找与“刘东阳”性别相同的所有学生的姓名、出生日期。"><a href="#1-在student-info表中查找与“刘东阳”性别相同的所有学生的姓名、出生日期。" class="headerlink" title="(1)在student_info表中查找与“刘东阳”性别相同的所有学生的姓名、出生日期。"></a>(1)在student_info表中查找与“刘东阳”性别相同的所有学生的姓名、出生日期。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`姓名`,c.`出生日期` FROM student_info c</span><br><span class="line"> WHERE c.`性别`=(SELECT c.`性别` FROM student_info c WHERE c.`姓名`=<span class="string">&#x27;刘东阳&#x27;</span>);</span><br></pre></td></tr></table></figure>
<h6 id="2-使用IN子查询查找所修课程编号为0002、0005的学生学号、姓名、性别。"><a href="#2-使用IN子查询查找所修课程编号为0002、0005的学生学号、姓名、性别。" class="headerlink" title="(2)使用IN子查询查找所修课程编号为0002、0005的学生学号、姓名、性别。"></a>(2)使用IN子查询查找所修课程编号为0002、0005的学生学号、姓名、性别。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名`,c.`性别` FROM student_info c</span><br><span class="line"> WHERE c.`学号` IN   ( SELECT d.`学号` FROM grade d WHERE  d.`课程编号` IN(<span class="string">&#x27;0002&#x27;</span>,<span class="string">&#x27;0005&#x27;</span>));</span><br></pre></td></tr></table></figure>
<h6 id="3-使用ANY子查询查找学号为0001的学生的分数比0002号的学生的最低分数高的课程编号和分数。"><a href="#3-使用ANY子查询查找学号为0001的学生的分数比0002号的学生的最低分数高的课程编号和分数。" class="headerlink" title="(3)使用ANY子查询查找学号为0001的学生的分数比0002号的学生的最低分数高的课程编号和分数。"></a>(3)使用ANY子查询查找学号为0001的学生的分数比0002号的学生的最低分数高的课程编号和分数。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT d.`学号`,d.`课程编号`,d.`分数` FROM grade d</span><br><span class="line"> WHERE d.`学号`=<span class="string">&#x27;0001&#x27;</span> AND  d.`分数` &gt; ANY(SELECT d.`分数` FROM grade d WHERE d.`学号`=0002);</span><br></pre></td></tr></table></figure>
<h6 id="4-使用ALL子查询查找学号为0001的学生的分数比学号为0002的学生的最高成绩还要高的课程编号和分数。"><a href="#4-使用ALL子查询查找学号为0001的学生的分数比学号为0002的学生的最高成绩还要高的课程编号和分数。" class="headerlink" title="(4)使用ALL子查询查找学号为0001的学生的分数比学号为0002的学生的最高成绩还要高的课程编号和分数。"></a>(4)使用ALL子查询查找学号为0001的学生的分数比学号为0002的学生的最高成绩还要高的课程编号和分数。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT d.`学号`,d.`课程编号`,d.`分数` FROM grade d</span><br><span class="line"> WHERE d.`学号`=<span class="string">&#x27;0001&#x27;</span> AND  d.`分数` &gt; ALL(SELECT d.`分数` FROM grade d WHERE d.`学号`=0002);</span><br></pre></td></tr></table></figure>

<h4 id="七、连接查询"><a href="#七、连接查询" class="headerlink" title="七、连接查询"></a>七、连接查询</h4><h6 id="1-查询分数在80-90范围内的学生的学号、姓名、分数。"><a href="#1-查询分数在80-90范围内的学生的学号、姓名、分数。" class="headerlink" title="(1)查询分数在80-90范围内的学生的学号、姓名、分数。"></a>(1)查询分数在80-90范围内的学生的学号、姓名、分数。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名`,d.`分数` FROM student_info c, grade d</span><br><span class="line"> WHERE c.`学号` = d.`学号` AND d.`分数` BETWEEN 80 AND 90;</span><br></pre></td></tr></table></figure>
<h6 id="2-使用INNER-JOIN连接方式查询学习“数据库原理及应用”课程的学生学号、姓名、分数。"><a href="#2-使用INNER-JOIN连接方式查询学习“数据库原理及应用”课程的学生学号、姓名、分数。" class="headerlink" title="(2)使用INNER JOIN连接方式查询学习“数据库原理及应用”课程的学生学号、姓名、分数。"></a>(2)使用INNER JOIN连接方式查询学习“数据库原理及应用”课程的学生学号、姓名、分数。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># SELECT e.`课程名称` FROM curriculum e</span></span><br><span class="line">SELECT c.`学号`,c.`姓名`,d.`分数` FROM student_info c INNER JOIN grade d</span><br><span class="line"> ON c.`学号`=d.`学号` INNER JOIN curriculum e ON d.`课程编号`=e.`课程编号` </span><br><span class="line"> WHERE e.`课程名称`=<span class="string">&quot;数据库原理及应用&quot;</span>;</span><br></pre></td></tr></table></figure>
<h6 id="3-查询每个学生所选课程的最高成绩，要求列出学号、姓名、最高成绩。"><a href="#3-查询每个学生所选课程的最高成绩，要求列出学号、姓名、最高成绩。" class="headerlink" title="(3)查询每个学生所选课程的最高成绩，要求列出学号、姓名、最高成绩。"></a>(3)查询每个学生所选课程的最高成绩，要求列出学号、姓名、最高成绩。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名`,max(d.`分数`)AS 最高成绩 FROM student_info c,grade d</span><br><span class="line"> WHERE c.`学号`=d.`学号` GROUP BY c.`学号`;</span><br></pre></td></tr></table></figure>
<h6 id="4-使用左外连接查询每个学生的总成绩，要求列出学号、姓名、总成绩，没有选修课程的学生的总成绩为空。"><a href="#4-使用左外连接查询每个学生的总成绩，要求列出学号、姓名、总成绩，没有选修课程的学生的总成绩为空。" class="headerlink" title="(4)使用左外连接查询每个学生的总成绩，要求列出学号、姓名、总成绩，没有选修课程的学生的总成绩为空。"></a>(4)使用左外连接查询每个学生的总成绩，要求列出学号、姓名、总成绩，没有选修课程的学生的总成绩为空。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">SELECT c.`学号`,c.`姓名`,SUM(d.`分数`)总成绩 FROM student_info c </span><br><span class="line"> LEFT OUTER JOIN grade d ON c.`学号`=d.`学号`GROUP BY c.`学号`;</span><br></pre></td></tr></table></figure>
<h6 id="5-为grade表添加数据行：学号为0004、课程编号为0006、分数为76。"><a href="#5-为grade表添加数据行：学号为0004、课程编号为0006、分数为76。" class="headerlink" title="(5)为grade表添加数据行：学号为0004、课程编号为0006、分数为76。"></a>(5)为grade表添加数据行：学号为0004、课程编号为0006、分数为76。</h6><h6 id="使用右外连接查询所有课程的选修情况，要求列出课程编号、课程名称、选修人数，curriculum表中没有的课程列值为空。"><a href="#使用右外连接查询所有课程的选修情况，要求列出课程编号、课程名称、选修人数，curriculum表中没有的课程列值为空。" class="headerlink" title="使用右外连接查询所有课程的选修情况，要求列出课程编号、课程名称、选修人数，curriculum表中没有的课程列值为空。"></a>使用右外连接查询所有课程的选修情况，要求列出课程编号、课程名称、选修人数，curriculum表中没有的课程列值为空。</h6><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">INSERT INTO grade VALUES (<span class="string">&#x27;0004&#x27;</span>,<span class="string">&#x27;0006&#x27;</span>,<span class="string">&#x27;76&#x27;</span>) </span><br><span class="line">SELECT d.`课程编号`,e.`课程名称`,COUNT(*)选修人数 FROM grade d</span><br><span class="line"> RIGHT OUTER JOIN curriculum e ON d.`课程编号`=e.`课程编号` GROUP BY d.`课程编号`;</span><br></pre></td></tr></table></figure>
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